System and method for delivering and deploying an occluding device within a vessel

ABSTRACT

A system and method for deploying an occluding device that can be used to remodel an aneurysm within the vessel by, for example, neck reconstruction or balloon remodeling. The system comprises an introducer sheath and an assembly for carrying the occluding device. The assembly includes an elongated flexible member having an occluding device retaining member for receiving a first end of the occluding device, a proximally positioned retaining member for engaging a second end of the occluding device and a support surrounding a portion of the elongated flexible member over which the occluding device can be positioned.

This application is a continuation of U.S. application Ser. No.11/420,023, filed May 24, 2006, which is a continuation-in-part of U.S.application Ser. No. 11/136,398, filed May 25, 2005, now U.S. Pat. No.8,147,534, each of the above applications being expressly incorporatedherein by reference in its entirety.

FIELD OF THE INVENTION

The invention generally relates to a system and method for deliveringand deploying a medical device within a vessel, more particularly, itrelates to a system and method for delivering and deploying anendoluminal therapeutic device within the vasculature of a patient toembolize and occlude aneurysms, particularly cerebral aneurysms.

BACKGROUND ART OF THE INVENTION

Walls of the vasculature, particularly arterial walls, may develop areasof pathological dilatation called aneurysms. As is well known, aneurysmshave thin, weak walls that are prone to rupturing. Aneurysms can be theresult of the vessel wall being weakened by disease, injury or acongenital abnormality. Aneurysms could be found in different parts ofthe body with the most common being abdominal aortic aneurysms and brainor cerebral aneurysms in the neurovasculature. When the weakened wall ofan aneurysm ruptures, it can result in death, especially if it is acerebral aneurysm that ruptures.

Aneurysms are generally treated by excluding the weakened part of thevessel from the arterial circulation. For treating a cerebral aneurysm,such reinforcement is done in many ways including: (i) surgicalclipping, where a metal clip is secured around the base of the aneurysm;(ii) packing the aneurysm with small, flexible wire coils (micro-coils);(iii) using embolic materials to “fill” an aneurysm; (iv) usingdetachable balloons or coils to occlude the parent vessel that suppliesthe aneurysm; and (v) intravascular stenting.

Intravascular stents are known in the medical arts for the treatment ofvascular stenoses or aneurysms. Stents are prostheses that expandradially or otherwise within a vessel or lumen to provide supportagainst the collapse of the vessel.

In conventional methods of introducing a compressed stent into a vesseland positioning it within in an area of stenosis or an aneurysm, aguiding catheter having a distal tip is percutaneously introduced intothe vascular system of a patient. The guiding catheter is advancedwithin the vessel until its distal tip is proximate the stenosis oraneurysm. A guidewire positioned within an inner lumen of a second,inner catheter and the inner catheter are advanced through the distalend of the guiding catheter. The guidewire is then advanced out of thedistal end of the guiding catheter into the vessel until the distalportion of the guidewire carrying the compressed stent is positioned atthe point of the lesion within the vessel. Once the compressed stent islocated at the lesion, the stent may be released and expanded so that itsupports the vessel.

SUMMARY OF THE INVENTION

Aspects of the present invention include a system and method ofdeploying an occluding device within a vessel. The occluding device canbe used to remodel an aneurysm within the vessel by, for example, neckreconstruction or balloon remodeling. The occluding device can be usedto form a barrier that retains occlusion material such as a well knowncoil or viscous fluids, such as “ONYX” by Microtherapeutics, within theaneurysm so that introduced material will not escape from within theaneurysm. Also, during deployment, the length of the occluding devicecan be adjusted in response to friction created between the occludingdevice and an inner surface of a catheter. When this occurs, thedeployed length and circumferential size of the occluding device can bechanged as desired by the physician performing the procedure.

An aspect of the present invention includes a system for supporting anddeploying an occluding device. The system comprises an introducer sheathand an assembly for carrying the occluding device. The assembly includesan elongated flexible member having an occluding device retaining memberfor receiving a first end of the occluding device, a proximallypositioned retaining member for engaging a second end of the occludingdevice and a support surrounding a portion of the elongated flexiblemember over which the occluding device can be positioned.

Another aspect of the present invention includes a system for supportingand deploying an occluding device. The system comprises an assembly forcarrying the occluding device. The assembly comprises an elongatedmember including a flexible distal tip portion, a retaining member forreceiving a first end of the occluding device, and a support surroundinga portion of the elongated flexible member for supporting the occludingdevice.

A further aspect of the present invention comprises a method ofintroducing and deploying an occluding device within a vessel. Themethod includes the steps of introducing an elongated sheath includingan introducer sheath carrying a guidewire assembly into a catheter andadvancing the guidewire assembly out of the sheath and into thecatheter. The method also includes the steps of positioning an end ofthe catheter proximate an aneurysm, advancing a portion of the guidewireassembly out of the catheter and rotating a portion of the guidewireassembly while deploying the occluding device in the area of theaneurysm.

In another aspect an elongated flexible member supports and deploys anoccluding device and the occluding device may be expanded and retractedbased on input pressure. For example, air of fluid pressure may beapplied to the occluding device via the flexible member to cause theoccluding device to expand or retract.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a cross section of an occluding device delivery assembly andoccluding device according to an aspect of the invention;

FIG. 2 illustrates a catheter and introducer sheath shown in FIG. 1;

FIG. 3 is a partial cut away view of the introducer sheath of FIG. 2carrying a guidewire assembly loaded with an occluding device;

FIG. 4 is a cross section of the guidewire assembly illustrated in FIG.3;

FIG. 5 is a schematic view of the guidewire assembly of FIG. 4;

FIG. 6 is a second schematic view of the guidewire assembly of FIG. 4;

FIG. 7 illustrates the occluding device and a portion of the guidewireassembly positioned outside the catheter, and how a proximal end of theoccluding device begins to deploy within a vessel;

FIG. 8 illustrates a step in the method of deploying the occludingdevice;

FIG. 9 illustrates the deployment of the occluding device according toan aspect of the present invention;

FIG. 10 is a schematic view of a guidewire assembly according to anotherembodiment of the present invention; and

FIG. 11 is a schematic view of the deployed occluding device afterhaving been deployed by the guidewire assembly of FIG. 10.

FIG. 12 illustrates an example of an expanded occluding device thatexpands responsive to pressure.

FIG. 13 illustrates the occluding device of FIG. 12 after a negativepressure is applied to the occluding device.

FIG. 14 illustrates an example of release of the distal end of theoccluding device while the proximal end of the occluding device remainsattached to the delivery device.

FIG. 15 illustrates an example of a partially deployed occluding device.

FIG. 16 illustrates another example of a partially deployed occludingdevice.

FIG. 17 illustrates the example of FIG. 16 in which the occluding deviceis repositioned proximally in the blood vessel.

FIG. 18 illustrates an example of an expanded occluding device.

FIG. 19 illustrates the example of FIG. 18 after the occluding device isrepositioned within a blood vessel.

FIG. 20 illustrates an example of the occluding device in a retractedstate.

FIG. 21 illustrates an example of repositioning the occluding devicewhile the occluding device is retracted.

DETAILED DESCRIPTION OF THE INVENTION

An occluding device delivery assembly having portions with small crosssection(s) and which is highly flexible is described herein. FIG. 1illustrates an introducer sheath 10 according to an aspect of thepresent invention that receives, contains and delivers an occludingdevice 100 to a flexible micro-catheter 1 for positioning within thevasculature of an individual. The occluding device 100 can include thoseembodiments disclosed in copending U.S. patent application titled“Flexible Vascular Occluding Device”, U.S. Ser. No. 11/136,395, filed onMay 25, 2005, which is expressly hereby incorporated by reference in itsentirety.

A distal end 12 of the introducer sheath 10 is sized and configured tobe received within a hub 2 of the micro-catheter 1, as shown in FIGS. 1and 2. The hub 2 can be positioned at the proximal end of themicro-catheter 1 or at another location spaced along the length of themicro-catheter 1. The micro-catheter 1 can be any known micro-catheterthat can be introduced and advanced through the vasculature of apatient. In an embodiment, the micro-catheter has an inner diameter of0.047 inch or less. In another embodiment, the micro-catheter has aninner diameter of about 0.027 inch to about 0.021 inch. In analternative embodiment, the micro-catheter could have an inner diameterof about 0.025 inch. However, it is contemplated that the micro-catheter1 can have an inner diameter that is greater than 0.047 inch or lessthan 0.021 inch. After the introducer sheath 10 is positioned within thecatheter hub 2, the occluding device 100 can be advanced from theintroducer sheath 10 into the micro-catheter 1 in preparation fordeploying the occluding device 100 within the vasculature of thepatient.

The micro-catheter 1 may have at least one fluid introduction port 6located adjacent the hub 2 or at another position along its length. Theport 6 is preferably in fluid communication with the distal end of themicro-catheter 1 so that a fluid, e.g., saline, may be passed throughthe micro-catheter 1 prior to insertion into the vasculature forflushing out air or debris trapped within the micro-catheter 1 and anyinstruments, such as guidewires, positioned within the micro-catheter 1.The port 6 may also be used to deliver drugs or fluids within thevasculature as desired.

FIG. 3 illustrates the introducer sheath 10, an elongated flexibledelivery guidewire assembly 20 that is movable within the introducersheath 10 and the occluding device 100. As shown, the guidewire assembly20 and the occluding device 100, carried by the guidewire assembly 20,have not been introduced into the micro-catheter 1. Instead, asillustrated, they are positioned within the introducer sheath 10. Theintroducer sheath 10 may be made from various thermoplastics, e.g.,PTFE, FEP, HDPE, PEEK, etc., which may optionally be lined on the innersurface of the sheath or an adjacent surface with a hydrophilic materialsuch as PVP or some other plastic coating. Additionally, either surfacemay be coated with various combinations of different materials,depending upon the desired results.

The introducer sheath 10 may include drainage ports or purge holes (notshown) formed into the wall near the area covering the occluding device100. There may be a single hole or multiple holes, e.g., three holes,formed into introducer sheath 10. These purge holes allow for fluids,e.g., saline, to readily escape from in between the introducer sheath 10and the guidewire assembly 20 when purging the sheath prior topositioning the introducer sheath 10 in contact with the catheter hub 2,e.g., to remove trapped air or debris.

As shown in FIG. 4, the guidewire assembly 20 includes an elongatedflexible guidewire 21. The flexibility of the guidewire 21 allows theguidewire assembly 20 to bend and conform to the curvature of thevasculature as needed for positional movement of the occluding device100 within the vasculature. The guidewire 21 may be made of aconventional guidewire material and have a solid cross section.Alternatively, the guidewire 21 can be formed from a hypotube. In eitherembodiment, the guidewire 21 has a diameter D₅ ranging from about 0.010inch to about 0.020 inch. In an embodiment, the largest diameter of theguidewire 21 is about 0.016 inch. The material used for the guidewire 21can be any of the known guidewire materials including superelasticmetals, e.g., Nitinol. Alternatively, the guidewire 21 can be formed ofmetals such as stainless steel. Length L₄ of the guidewire can be fromabout 125 to about 190 cm. In an embodiment, the length L₄ is about 175cm.

The guidewire assembly 20 can have the same degree of flexion along itsentire length. In an alternative embodiment, the guidewire assembly 20can have longitudinal sections, each with differing degrees offlexion/stiffness. The different degrees of flexions for the guidewireassembly 20 can be created using different materials and/or thicknesseswithin different longitudinal sections of the guidewire 21. In anotherembodiment, the flexion of the guidewire 21 can be controlled by spacedcuts (not shown) formed within the delivery guidewire 21. These cuts canbe longitudinally and/or circumferentially spaced from each other. Thecuts can be formed with precision within the delivery guidewire 21.Different sections of the delivery guidewire 21 can include cuts formedwith different spacing and different depths to provide these distinctsections with different amounts of flexion and stiffness. In any of theabove embodiments, the guidewire assembly 20 and the guidewire 21 areresponsive to torque applied to the guidewire assembly 20 by theoperator. As discussed below, the torque applied to the guidewireassembly 20 via the guidewire 21 can be used to release the occludingdevice 100 from the guidewire assembly 20.

The size and shape of the cuts formed within the delivery guidewire 21may be controlled so as to provide greater or lesser amounts offlexibility. Because the cuts can be varied in width without changingthe depth or overall shape of the cut, the flexibility of the deliveryguidewire 21 may be selectively altered without affecting the torsionalstrength of the delivery guidewire 21. Thus, the flexibility andtorsional strength of the delivery guidewire 21 may be selectively andindependently altered.

Advantageously, longitudinally adjacent pairs of cuts may be rotatedabout 90 degrees around the circumference of the delivery guidewire 21from one another to provide flexure laterally and vertically. However,the cuts may be located at predetermined locations to providepreferential flexure in one or more desired directions. Of course, thecuts could be randomly formed to allow bending (flexion) equally,non-preferentially in all directions or planes. In one embodiment, thiscould be achieved by circumferentially spacing the cuts.

The flexible delivery guidewire 21 can include any number of sectionshaving the same or differing degrees of flexion. For example, theflexible delivery guidewire 21 could include two or more sections. Inthe embodiment illustrated in FIG. 4, the flexible delivery guidewire 21includes three sections, each having a different diameter. Each sectioncan have a diameter of about 0.003 inch to about 0.025 inch. In anembodiment, the diameter of one or more sections can be about 0.010 inchto about 0.020 inch. A first section 22 includes a proximal end 23 thatis located opposite the position of the occluding device 100. The firstsection 22 can have a constant thickness along its length.Alternatively, the first section 22 can have a thickness (diameter) thattapers along its entire length or only a portion of its length. In thetapered embodiment, the thickness (diameter) of the first section 22decreases in the direction of a second, transition section 24. For thoseembodiments in which the guidewire 21 has a circular cross section, thethickness is the diameter of the section.

The second, transition section 24 extends between the first section 22and a third, distal section 26. The second section 24 tapers inthickness from the large diameter of the first section 22 to the smallerdiameter of the third section 26. As with the first section 22, thesecond section 24 can taper along its entire length or only a portion ofits length.

The third section 26 has a smaller thickness compared to the othersections 22, 24 of the delivery guidewire 21. The third section 26extends away from the tapered second section 24 that carries theoccluding device 100. The third section 26 can taper along its entirelength from the second section 24 to the distal end 27 of the deliveryguidewire 21. Alternatively, the third section 26 can have a constantdiameter or taper along only a portion of its length. In such anembodiment, the tapering portion of the third section 26 can extend fromthe second section 24 or a point spaced from the second section 24 to apoint spaced from distal end 27 of the delivery guidewire 21. Althoughthree sections of the delivery guidewire 21 are discussed andillustrated, the delivery guidewire 21 can include more than threesections. Additionally, each of these sections can taper in theirthickness (diameter) along all or only a portion of their length. In anyof the disclosed embodiments, the delivery guidewire 21 can be formed ofa shape memory alloy such as Nitinol.

A tip 28 and flexible tip coil 29 are secured to the distal end 27 ofthe delivery guidewire 21 as shown in FIGS. 4 and 5. The tip 28 caninclude a continuous end cap or cover as shown in the figures, whichsecurely receives a distal end of the tip coil 29. Flexion control isprovided to the distal end portion of the delivery guidewire 21 by thetip coil 29. However, in an embodiment, the tip 28 can be free of thecoil 29. The tip 28 has a non-percutaneous, atraumatic end face. In theillustrated embodiment, the tip 28 has a rounded face. In alternativeembodiments, the tip 28 can have other non-percutaneous shapes that willnot injure the vessel in which it is introduced. As illustrated in FIG.4, the tip 28 includes a housing 45 that securely receives the distalend of the guidewire 21 within an opening 46 in the interior surface ofthe housing 45. The guidewire 21 can be secured within the opening byany known means.

As shown in FIG. 4, the tip coil 29 surrounds a portion of the guidewire21. The tip coil 29 is flexible so that it will conform to and followthe path of a vessel within the patient as the tip 28 is advanced alongthe vessel and the guidewire 21 bends to follow the tortuous path of thevasculature. The tip coil 29 extends rearward from the tip 28 in thedirection of the proximal end 23, as shown.

The tip 28 and coil 29 have an outer diameter D₁ of about 0.010 inch toabout 0.018 inch. In an embodiment, their outer diameter D₁ is about0.014 inch. The tip 28 and coil 29 also have a length L₁ of about 0.1 cmto about 3.0 cm. In an embodiment, they have a total length L₁ of about1.5 cm.

A proximal end 30 of the tip coil 29 is received within a housing 32 ata distal end 24 of a protective coil 35, as shown in FIGS. 1 and 4. Thehousing 32 and protective coil 35 have an outer diameter D₂ of about0.018 inch to about 0.038 inch. In an embodiment, their outer diameterD₂ is about 0.024 inch. The housing 32 and protective coil 35 have alength L₂ of about 0.05 cm to about 0.2 cm. In an embodiment, theirtotal length L₂ is about 0.15 cm.

The housing 32 has a non-percutaneous, atraumatic shape. For example, asshown in FIG. 5, the housing 32 has a substantially blunt profile. Also,the housing 32 can be sized to open/support the vessel as it passesthrough it. Additionally, the housing 32 can include angled sidewallssized to just be spaced just off the inner surface of the introducersheath 10.

The housing 32 and protective coil 35 form a distal retaining memberthat maintains the position of the occluding device 100 on the flexibleguidewire assembly 20 and helps to hold the occluding device 100 in acompressed state prior to its delivery and deployment within a vessel ofthe vasculature. The protective coil 35 extends from the housing 32 inthe direction of the proximal end 23 of the delivery guidewire 21, asshown in FIG. 4. The protective coil 35 is secured to the housing 32 inany known manner. In a first embodiment, the protective coil 35 can besecured to the outer surface of the housing 32. In an alternativeembodiment, the protective coil 35 can be secured within an opening ofthe housing 32 so that the housing 32 surrounds and internally receivesthe distal end 51 of the protective coil 35 (FIG. 4). As shown in FIGS.3 and 4, the distal end 102 of the occluding device 100 is retainedwithin the proximal end 52 so that the occluding device 100 cannotdeploy while positioned in the sheath 10 or the micro-catheter 1.

At the proximal end of the occluding device 100, a bumper coil 60 andcap 62 prevent lateral movement of the occluding device 100 along thelength of the guidewire 21 in the direction of the proximal end 23, seeFIG. 3. The bumper coil 60 and cap 62 have an outer diameter D₄ of about0.018 inch to about 0.038 inch. In an embodiment, their outer diameterD₄ is about 0.024 inch. The cap 62 contacts the proximal end 107 of theoccluding device 100 and prevents it from moving along the length of theguidewire 21 away from the protective coil 35. The bumper coil 60 can bein the form of a spring that contacts and pressures the cap 62 in thedirection of the protective coil 35, thereby creating a biasing forceagainst the occluding device 100. This biasing force (pressure) aids inmaintaining the secured, covered relationship between the distal end 102of the occluding device 100 and the protective coil 35. As with any ofthe coils positioned along the delivery guidewire 21, the bumper coil 60can be secured to the delivery guidewire 21 by soldering, welding, RFwelding, glue, and/or other known adhesives.

In an alternative embodiment illustrated in FIG. 10, the bumper coil 60is not utilized. Instead, a proximal end 107 of the occluding device 100is held in position by a set of spring loaded arms (jaws) 140 whilepositioned within the introducer sheath 10 or the micro-catheter 1. Theinner surfaces of the micro-catheter 1 and the introducer sheath 10limit the radial expansion of the arms 140. When the proximal end of theoccluding device passes out of the micro-catheter 1, the arms 140 wouldspring open and release the occluding device as shown in FIG. 11.

In another example, the occluding device 100 in the introducer sheath 10or the micro-catheter 1 may expand within a vessel under pressure. FIG.12 illustrates an example of an expanded occluding device 100 thatexpands responsive to pressure. Pressure may be applied through themicro-catheter 1 or the introducer sheath 10 as the occluding device 100passes out of the micro-catheter 1. The pressure may be exerted throughapplication of air, fluid, or any material for increasing the internalpressure of the occluding device. The increase in pressure within theoccluding device 100 when the occluding device 100 passes out of themicro-catheter 1 may cause the occluding device to expand within thevessel. Conversely, a negative pressure may be exerted at the occludingdevice 100. FIG. 13 illustrates the occluding device 100 of FIG. 12after a negative pressure is applied to the occluding device 100. Thenegative pressure may be applied via the micro-catheter 1 or theintroducer sheath 10 and may cause the occluding device 100 to retractor decrease in size. In one example, a negative pressure is exerted atthe occluding device 100 after the occluding device 100 is passed out ofthe micro-catheter 1 and expanded in the vessel. The negative pressurecauses the occluding device 100 to retract. Upon retraction, theoccluding device 100 may be reduced in size. In another example, theoccluding device 100 may be replaced back into the microcatheter 1 afterretraction. The negative pressure may be applied in a variety of ways.For example, the negative pressure may be applied by suction of air fromthe micro-catheter 1 or by removal or suction of fluid from themicro-catheter 1.

Also, in another example, the occluding device 100 may be expanded, forexample, by application of increased pressure within the occludingdevice. The increased pressure may be administered via the deliverydevice by, for example, injecting air or fluid via the delivery deviceto the occluding device 100. The occluding device 100 may thus beexpanded in a vessel such that the occluding device 100 may come intocontact with the internal aspect of the wall of the vessel. In this way,at least a portion of the occluding device 100, while in the expandedstate, may contact the wall of the vessel.

While in the expanded state, the occluding device 100 may berepositioned within the vessel. FIG. 18 illustrates an example of anexpanded occluding device 100. FIG. 19 illustrates the example of FIG.18 after the occluding device is repositioned within a blood vessel. Inthis example, the occluding device 100 may be expanded in a longitudinalaxis along the vessel such that the occluding device 100 may move withinthe vessel while expanded. Pressure may be exerted by a user at aproximal end of the occluding device 100 such that the proximal end ismoved distally within the vessel lumen. At the same time, frictionalforces between the wall of the vessel and the more distal portions ofthe occluding device may prevent immediate movement of the more distalportions of the occluding device. When the pressure or force exerted atthe proximal end exceeds a threshold level, the force may be transmittedto the more distal portions of the occluding device to cause the moredistal portions of the occluding device to more distally in the lumen ofthe vessel. In this way, the occluding device may move distally in thevessel lumen and may be repositioned at a desired location within thevessel by the user. FIG. 19 illustrates distal repositioning of theoccluding device in a blood vessel.

Similarly, the occluding device may be repositioned more proximally inthe vessel lumen by the user. For example, the user may provide a forceor pressure at a distal portion of the occluding device in a proximaldirection. The distal portion of the occluding device may moveproximally while frictional forces between the more proximal portions ofthe occluding device prevent initial movement of the more proximalportions of the occluding device. Hence, in this example, the occludingdevice compresses at a portion intermediate between the distal portionand the more proximal portions of the occluding device. When thepressure or force exerted by the user at the distal portion of theoccluding device exceeds a threshold level that exceeds the frictionalforce preventing movement of the more proximal portions of the occludingdevice, the more proximal portions of the occluding device may move in aproximal direction responsive to the applied pressure or force. In thisway, the occluding device may be repositioned proximally in the vessel.

In another example, the occluding device 100 may be repositioned in ablood vessel while the occluding device 100 is in a retracted state.FIG. 20 illustrates an example of the occluding device 100 in aretracted state. For example, negative pressure may be exerted at theoccluding device 100 of FIG. 12 to cause the occluding device 100 todecrease in size as illustrated in FIG. 20. The occluding device 100 asillustrated in FIG. 20 is retracted and approximates the deliverydevice. FIG. 21 illustrates an example of repositioning the occludingdevice 100 while the occluding device is retracted. As FIG. 21illustrates, the occluding device is moved in a distal direction.Similarly, the occluding device may also be repositioned in a proximaldirection (not shown).

Also, deployment of the occluding device may be performed in parts. Forexample, the occluding device 100 may have a distal end and a proximalend. Deployment of the occluding device may include release of a distalend followed by release of the proximal end of the occluding device.Alternatively, deployment of the occluding device may include release ofthe proximal end followed by release of the distal end. Also, deploymentof the occluding device may include release of the proximal end and thedistal end of the occluding device 100 at approximately the same time.

FIG. 14 illustrates an example of release of the distal end of theoccluding device 100 while the proximal end of the occluding deviceremains attached to the delivery device. As FIG. 14 shows, the distalend of the occluding device 100 is deployed and abuts the wall of theblood vessel. The proximal end of the occluding device 100 is stillattached to the delivery device. Release of the proximal end of theoccluding device may be accomplished in a variety of ways as describedherein.

In addition, the partially deployed occluding device 100 as illustratedin FIG. 14 may be repositioned in the blood vessel. FIG. 15 illustratesan example of a partially deployed occluding device 100 in which thedistal end of the occluding device 100 has been released from thedelivery device while the proximal end of the delivery device 100remains attached and non-deployed to the delivery device. In addition,FIG. 15 demonstrates repositioning of the occluding device whilepartially deployed. As FIG. 15 shows, the delivery device and occludingdevice 100 has been moved proximally in the blood vessel. Also, FIG. 15illustrates that the occluding device is partially deployed in the bloodvessel such that the distal end of the occluding device is released fromthe delivery device while the proximal end of the occluding device 100remains attached to the delivery device.

Alternatively, the proximal end of the occluding device may be releasedfrom the delivery device while the distal end of the occluding deviceremains attached to the delivery device. The distal end of the occludingdevice may then be deployed or released from the delivery device at asubsequent time. FIG. 16 illustrates an example of a partially deployedoccluding device 100 in a blood vessel in which the proximal end of theoccluding device 100 is released from the delivery device while thedistal end of the occluding device remains attached to the deliverydevice. The proximal end of the occluding device 100 thus approximatesthe walls of the blood vessel.

FIG. 17 illustrates the example of FIG. 16 in which the occluding device100 is repositioned proximally in the blood vessel. In this example, theoccluding device is partially deployed such that the proximal end of theoccluding device 100 is released from the delivery device while thedistal end of the occluding device 100 is attached. The occluding deviceis then moved or repositioned to a more proximal location within theblood vessel. Alternatively, the occluding device may also be moved orrepositioned to a more distal location within the blood vessel (notshown).

In an alternative embodiment, the bumper coil 60 and cap 62 can beeliminated and the proximal end of the occluding device 100 can be heldin position relative to the protective coil 35 by a tapered section ofthe guidewire 21. In such an embodiment, the enlarged cross section ofthis tapered section can be used to retain the occluding device 100 inposition along the length of the delivery guidewire 21 and preventmovement of the occluding device 100 in the direction of the proximalend 23.

As shown in FIG. 4, the guidewire assembly 20 includes a support 70 forthe occluding device 100. In a first embodiment, the support 70 caninclude an outer surface of the delivery guidewire 21 that is sized tocontact the inner surface of the occluding device 100 when the occludingdevice 100 is loaded on the guidewire assembly 20. In this embodiment,the outer surface of the delivery guidewire 21 supports the occludingdevice 100 and maintains it in a ready to deploy state. In anotherembodiment, illustrated in the Figures, the support 70 comprises amid-coil 70 that extends from a location proximate the protective coil35 rearward toward the bumper coil 60. The mid-coil 70 extends under theoccluding device 100 and over the delivery guidewire 21, as shown inFIG. 1. The mid-coil 70 can be coextensive with one or more sections ofthe delivery guidewire 21. For example, the mid-coil 70 could becoextensive with only the second section 24 of the delivery guidewire 21or it could extend along portions of both the third section 26 and thesecond section 24 of the delivery guidewire 21.

The mid-coil 70 provides the guidewire assembly 20 with an outwardlyextending surface that is sized to contact the inner surface of theoccluding device 100 in order to assist in supporting the occludingdevice and maintaining the occluding device 100 in a ready to deploystate. Like the other coils discussed herein and illustrated in thefigures, the coiled form of the mid-coil 70 permits the mid-coil 70 toflex with the delivery guidewire 21 as the delivery guidewire 21 isadvanced through the vasculature of the patient. The mid-coil 70provides a constant diameter along a length of the delivery guidewire 21that is covered by the occluding device 100 regardless of the taper ofthe delivery guidewire 21 beneath the occluding device 100. The mid-coil70 permits the delivery guidewire 21 to be tapered so it can achieve theneeded flexibility to follow the path of the vasculature withoutcompromising the support provided to the occluding device 100. Themid-coil 70 provides the occluding device 100 with constant supportregardless of the taper of the delivery guidewire 21 prior to theoccluding device 100 being deployed. The smallest diameter of theoccluding device 100 when in its compressed state is also controlled bythe size of the mid-coil 70. Additionally, the diameter of the mid-coil70 can be chosen so that the proper spacing, including no spacing, isestablished between the occluding device 100 and the inner wall of themicro-catheter 1 prior to deployment of the occluding device 100. Themid-coil 70 can also be used to bias the occluding device 100 away fromthe delivery guidewire 21 during its deployment.

In either embodiment, the support 70 can have an outer diameter D₃ ofabout 0.010 inch to about 0.018 inch. In an embodiment, the outerdiameter D₃ is about 0.014 inch. The support 70 can also have a lengthL₃ of about 2.0 cm to about 30 cm. In an embodiment, the length L₃ ofthe support 70 is about 7 cm.

The occluding device 100 may also be placed on the mid-coil 70 betweenan optional pair of radio-opaque marker bands located along the lengthof the guidewire assembly 20. Alternatively, the protective coil 35,bumper coil 60 and or mid-coil 70 can include radio-opaque markers. Inan alternative embodiment, the guidewire assembly 20 may include only asingle radio-opaque marker. The use of radio-opaque markers allows forthe visualization of the guidewire assembly 20 and the occluding device100 during placement within the vasculature. Such visualizationtechniques may include conventional methods such as fluoroscopy,radiography, ultra-sonography, magnetic resonance imaging, etc.

The occluding device 100 can be delivered and deployed at the site of ananeurysm according to the following method and variations thereof. Thedelivery of the occluding device 100 includes introducing themicro-catheter 1 into the vasculature until it reaches a site thatrequires treatment. The micro-catheter 1 is introduced into thevasculature using a conventional technique such as being advanced overor simultaneously with a conventional vascular guidewire (not shown).The positioning of the micro-catheter 1 can occur before it receives theguidewire assembly 20 or while it contains the guidewire assembly 20.The position of the micro-catheter 1 within the vasculature can bedetermined by identifying radio-opaque markers positioned on or in themicro-catheter 1.

After the micro-catheter 1 is positioned at the desired location, theguidewire is removed and the distal end of the introducer sheath 10 isinserted into the proximal end of the micro-catheter 1, as shown inFIG. 1. In an embodiment, the distal end of the introducer sheath 10 isintroduced through the hub 2 at the proximal end of the micro-catheter1. The introducer sheath 10 is advanced within the micro-catheter 1until a distal tip of the introducer sheath 10 is wedged within themicro-catheter 1. At this position, the introducer sheath 10 cannot beadvanced further within the micro-catheter 1. The introducer sheath 10is then securely held while the delivery guidewire assembly 20 carryingthe occluding device 100 is advanced through the introducer sheath 10until the occluding device 100 is advanced out of the introducer sheath10 and into the micro-catheter 1.

The guidewire assembly 20 and the occluding device 100 are advancedthrough the micro-catheter 1 until the tip coil 29 is proximate thedistal end of the micro-catheter 1. At this point, the position of themicro-catheter 1 and guidewire assembly 20 can be confirmed. Theguidewire assembly 20 is then advanced out of the micro-catheter 1 andinto the vasculature of the patient so that the proximal end 107 of theoccluding device 100 is positioned outside the distal end of themicro-catheter 1 and adjacent the area to be treated. At any pointduring these steps, the position of the occluding device 100 can bechecked to determine that it will be deployed correctly and at thedesired location. This can be accomplished by using the radio-opaquemarkers discussed above.

When the distal end 102 of the occluding device 100 is positionedoutside the micro-catheter 1, the proximal end 107 will begin to expand,in the direction of the arrows shown in FIG. 7, within the vasculaturewhile the distal end 102 remains covered by the protective coil 35. Whenthe occluding device 100 is in the proper position, the deliveryguidewire 21 is rotated (See FIG. 8) until the distal end 102 of theoccluding device 100 moves away from the protective coil 35 and expandswithin the vasculature at the desired location. The delivery guidewire21 can be rotated either clockwise or counter clockwise as needed todeploy the occluding device 100. In an embodiment, the deliveryguidewire 21 may be rotated, for example, between two and ten turns ineither or both directions. In another example, the occluding device maybe deployed by rotating the delivery guidewire 21 clockwise for lessthan five turns, for example, three to five turns. After the occludingdevice 100 has been deployed, the delivery guidewire 21 can be retractedinto the micro-catheter 100 and removed form the body.

In one alternative or additional deployment method, the distal end 102of the occluding device 100 may be passed outside of the micro-catheter1. The occluding device 100 may be further advanced so that the proximalend 107 of the occluding device 100 passes outside of themicro-catheter. However, in this example, the proximal end 107 of theoccluding device 100 expands responsive to the application of pressureto the inner surfaces of the occluding device 100. The applied pressuremay be from any source. Examples of pressure exerted in the occludingdevice 100 include, but are not limited to, infusion of fluid or airinto the lumen of the occluding device.

The increase in pressure in the occluding device may cause the occludingdevice 100 to expand. Expansion of the occluding device 100 may cause adisconnection of the proximal end 107 of the occluding device 100 and/orthe distal end 102 of the occluding device 100 such that the occludingdevice may substantially fill the lumen of the vessel. Alternatively,the increase in pressure in the occluding device may expand theoccluding device 100 without detachment of either the proximal end 107or the distal end 102 of the occluding device 100. In this example, theoccluding device 100 may be expanded without detaching the occludingdevice 100 from the delivery system. The expanded occluding device 100may be adjusted and moved within the vessel in the expanded state whileconnected to the delivery system. When the occluding device 100 is at adesired location in the vessel, the occluding device 100 may be releasedfrom the delivery system. Release of the occluding device 100 from thedelivery system may be accomplished in a variety of ways as describedherein.

In addition, the coverage of the occluding device 100 may be adjustedwhile the occluding device is expanded and connected to the deliverysystem. For example, the occluding device 100 may be unsheathed from themicro-catheter 1 and expanded under pressure (e.g., from fluid or air)such that the occluding device 100 is expanded in the vessel. Theposition of the occluding device 100 may be further adjusted. Also, thepressure applied within the occluding device 100 may be adjusted toincrease the size of the expanded occluding device 100 in the vessel.Relative adjustments of the size of the expanded occluding device 100(i.e., by adjusting the amount of pressure applied to the occludingdevice 100) and of the position or location of the occluding device 100permit control of coverage of the occluding device when placed in thevessel.

Also, a negative pressure may be applied (e.g., air suction or removalof fluid from within the occluding device 100) to cause the occludingdevice to retract. The retracted occluding device 100 may further beplaced back into the micro-catheter 1. In one example, the occludingdevice 100 may be expanded and retracted as desired for movement orplacement of the occluding device 100 within the vessel.

In an alternative or additional deployment step shown in FIG. 9,friction between the occluding device 100 and inner surface of themicro-catheter 1 cause the distal end of the occluding device 100 toseparate from the protective coil 35. The friction can be created by theopening of the occluding device 100 and/or the mid-coil 70 biasing theoccluding device 100 toward the inner surface of the micro-catheter 1.The friction between the micro-catheter 1 and the occluding device 100will assist in the deployment of the occluding device 100. In thoseinstances when the occluding device 100 does not open and separate fromthe protective coil 35 during deployment, the friction between occludingdevice 100 and the inner surface of the micro-catheter 1 will cause theoccluding device 100 to move away from the protective coil 35 as thedelivery guidewire 21 and the micro-catheter 1 move relative to eachother. The delivery guidewire 21 can then be rotated and the occludingdevice 100 deployed within the vessel.

After the occluding device 100 radially self-expands into gentle, butsecure, contact with the walls of the vessel so as to occlude the neckof the aneurysm A, the micro-catheter 1 may be removed entirely from thebody of the patient. Alternatively, the micro-catheter 1 may be left inposition within vasculature to allow for the insertion of additionaltools or the application of drugs near the treatment site.

Known materials can be used in the present invention. One commonmaterial that can be used with the occluding device 100 and theguidewire 21 is Nitinol, a nickel-titanium shape memory alloy, which canbe formed and annealed, deformed at a low temperature, and recalled toits original shape with heating, such as when deployed at bodytemperature in the body. The radio-opaque markers can be formed ofradio-opaque materials including metals, such as platinum, or dopedplastics including bismuth or tungsten to aid in visualization.

The apparatus and methods discussed herein are not limited to thedeployment and use within the vascular system but may include any numberof further treatment applications. Other treatment sites may includeareas or regions of the body such as organ bodies. Modification of eachof the above-described apparatus and methods for carrying out theinvention, and variations of aspects of the invention that are obviousto those of skill in the art are intended to be within the scope of theclaims. Furthermore, no element, component or method step is intended tobe dedicated to the public regardless of whether the element, componentor method step is explicitly recited in the claims.

What is claimed:
 1. A method for introducing a stent within a vessel,said method comprising: introducing a delivery assembly into a catheter,the delivery assembly comprising (i) an elongate flexible member; and(ii) a retaining member having an inner lumen that extends around acircumference of a distal portion of the elongate member, the lumenreceiving a first end of the stent to secure a portion of the stent inthe retaining member; positioning an end of the catheter proximate ananeurysm; advancing at least a portion of the delivery assembly out ofthe catheter; expanding at least a portion of the stent by applying aforce against an internal portion of the stent; rotating the retainingmember relative to the stent, whereby the first end moves proximallyrelative to the retaining member and is released from within the lumen.2. The method of claim 1, wherein the force comprises a pressure that isapplied as the delivery assembly is advanced out of said catheter. 3.The method of claim 1, wherein the force comprises a pressure that isapplied via the catheter.
 4. The method according to claim 1, whereinthe stent is a self-expanding device.
 5. The method according to claim1, wherein the retaining member comprises a protective coil.
 6. Themethod according to claim 1, wherein the first end of the stent isbiased radially outwardly against the retaining member.
 7. A method forpositioning a self-expanding stent at a treatment site in a vessel, themethod comprising: introducing a catheter into the vessel; advancing atleast a portion of a delivery assembly out of a distal end of thecatheter, the delivery assembly comprising an elongate flexible memberand a retaining member at a distal end of the elongate flexible member,the retaining member receiving a first end of the self-expanding stent,the stent being concentrically constrained within the retaining memberand configured to radially expand against an internal surface of a lumenof the retaining member; expanding a distal portion of the stent againsta vessel wall; advancing the stent, after expanding the distal end, in adistal direction in the vessel by applying a force at a proximal portionof the stent; and rotating the delivery assembly to release the firstend of the stent from the retaining member by moving the first endproximally relative to the retaining member.
 8. The method of claim 7,wherein the force exceeds a frictional force between the distal portionof the stent and the vessel wall.
 9. The method of claim 8, wherein thefrictional force between the distal portion of the stent and the vesselwall prevents immediate movement of the distal portion of the stent. 10.The method according to claim 7, wherein the retaining member comprisesa protective coil, and the stent first end is received within aninterior of the protective coil.
 11. The method according to claim 7,further comprising holding the catheter stationary while rotating thedelivery assembly.